hbecher/sequence-js
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Hervé BECHER
2025-09-10 10:21:37 +02:00
parent 637991c394
commit 806d735c35
20 changed files with 480 additions and 259 deletions
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14
src/random/index.ts
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@@ -1,6 +1,6 @@
import { BitArray } from "../bitarray/index.js";
import { asArray } from "../utils.js";
import { AsyncRandomOptions, ElementPredicate, ElementWeight, RandomGenerator, RandomOptions } from "./types.js";
import { AsyncRandomOptions, ElementPredicate, ElementWeight, RandomElement, RandomGenerator, RandomOptions } from "./types.js";
export const alwaysTrue: ElementPredicate = () => true;
export const weightOfOne: ElementWeight = () => 1.0;
@@ -45,9 +45,10 @@ function withDefaultOptions<T>(options: RandomOptions<T> | AsyncRandomOptions<T>
};
}
function _getRandomElement<T>(sequence: Iterable<T>, options: Required<RandomOptions<T>>) {
function _getRandomElement<T>(sequence: Iterable<T>, options: Required<RandomOptions<T>>): RandomElement<T> {
const { predicate, weight, random } = options;
let found = false;
let result: T | undefined = undefined;
let resultIndex = -1;
let index = 0;
@@ -66,22 +67,24 @@ function _getRandomElement<T>(sequence: Iterable<T>, options: Required<RandomOpt
weightAcc += w;
if (random() * weightAcc < w) {
found = true;
result = element;
resultIndex = currentIndex;
}
}
}
return { element: result, index: resultIndex };
return { found, element: result, index: resultIndex } as RandomElement<T>;
}
export function getRandomElement<T>(sequence: Iterable<T>, options?: RandomOptions<T>) {
return _getRandomElement(sequence, withDefaultOptions(options));
}
async function _getRandomElementAsync<T>(sequence: AsyncIterable<T>, options: Required<AsyncRandomOptions<T>>) {
async function _getRandomElementAsync<T>(sequence: AsyncIterable<T>, options: Required<AsyncRandomOptions<T>>): Promise<RandomElement<T>> {
const { predicate, weight, random } = options;
let found = false;
let result: T | undefined = undefined;
let resultIndex = -1;
let index = 0;
@@ -100,13 +103,14 @@ async function _getRandomElementAsync<T>(sequence: AsyncIterable<T>, options: Re
weightAcc += w;
if (random() * weightAcc < w) {
found = true;
result = element;
resultIndex = currentIndex;
}
}
}
return { element: result, index: resultIndex };
return { found, element: result, index: resultIndex } as RandomElement<T>;
}
export async function getRandomElementAsync<T>(sequence: AsyncIterable<T>, options?: AsyncRandomOptions<T>) {